在UNNotificationService扩展中修改推送通知负载中的‘声音’属性

import UserNotifications

class NotificationService: UNNotificationServiceExtension {
    var contentHandler: ((UNNotificationContent) -> Void)?
    var bestAttemptContent: UNMutableNotificationContent?

    override func didReceive(_ request: UNNotificationRequest, withContentHandler contentHandler: @escaping (UNNotificationContent) -> Void) {
        self.contentHandler = contentHandler
        bestAttemptContent = (request.content.mutableCopy() as? UNMutableNotificationContent)

        if let bestAttemptContent = bestAttemptContent {
            // 修改声音属性
            bestAttemptContent.sound = UNNotificationSound.default

            // 调用contentHandler闭包并传递修改后的内容
            contentHandler(bestAttemptContent)
        }
    }
}